Control mechanism for hydraulic elevators



A. B. ROVER. CONTROL MECHANISM FOR HYDRAULIC ELEVATORS.

I APPLICATION FILED NOV. 2. 1916. LSD/R56,

6 SHEETS-SHEET l- IN VE/VTOR flTTaR/ws v Patented June 2-1, 1919.,

A. B. ROVER. CONTROL MECHANISM FOR HYDRAULIC ELEVATORS. APPLICATION FILED NOV. 2. I9I6.

Patented June 24., I919.

v A. B. ROVER. CONTROL MECHANISM FOR HYDRAULIC ELEVATORS.

r APPLICATION FILED NOV 2. I9l5. 1,807,756

6 SHEETS-SHEET 3' Patented June 24, 1919.

Ita J I. 8 x Z I ATTORNEY.

Patented June 24, 1919.

6 SHEETS--SHEET 4.

I4 fro/mu; y.

A. B. ROVER. CONTROL MECHANISM FOR HYDRAULIC ELEVATORS APPLICATION FILED NOV. 2. I9I6. 1307,7560

I IN a ma WINE. '5 1S AL 8, ROVER. CONTROL MECHANISM FOR HYDRAULIC ELEVATORS.

APPLICATION FILED NOV- 2 915. 1 3071756. Patented June 24, 1919.

6 SHEETS-SHEET 5.

fiTTORNEY TfirLlf/im. WASHINGTON. n. c.

A. B. ROVER CONTROL MECHANISM FOR HYDRAULIC ELEVATORS.

- APPLICATION FILED NOV. 2. ms.

Patented June 24, 1919.

6 SHEETS-SHEET 6.

ATTORNEY.

'm: NORRIS PETERS cu. PHOPO-LITHO., wasmlvcmu. B, c.

UNITED sTATEs PATENT oEEIoE.

AnoLrH B. ROVER, 0E BmeHAMToN, NEW Yo-nK, Assmnon. OF ONEJ-IALF To sEoneE;

A. REYNOLDS AND SAMUEL W. REYNOLDS, BOTH OF BINGHAMTON, NEW YORK.

CONTROL nncnnnrsivi on. Hvnnnumo ELEVATORS.

Original application filed December 27,1912, Serial No. 738,900. Divided and this application filed Novem li her 2, 1916. Serial No. 129,095.

To all whom it may concern:

Be it known that I, AnoLrH B. Rovnm a citizen of the United States of America, and resident of Binghamton, in the county of Brooms, in the State of New York, have invented new and useful Improvements in Control Mechanism for Hydraulic Eleva tors, of which the following, taken in 0on5 nection with the accompanying drawings, is a full, clear, and eXact description.

This invention relates tocertain improve ments in hydraulic elevators of theclass set forth in my Patents Nos. 1,206,763 and 1,206,764, both issued November 28, 1916,

except that it refers more particularly to external mechanism for controlling the op erati on of the car through the medium of an auxiliary controller which forms the sub jects-matter of those two applications, the present application being division of my parent application, resulting in Patent No.

1,206,763, above referred to;

The main object is to provide means ex ternal to the car by which said carmay be started at will from and automatically stopped at any one of the several floors through which it is adapted to pass, and at the same time to utilize the automatic stopping mechanism for restoring andmaintaim ingthe car at the fioorlevel at which it has been stopped in case it should tend to settle under its own weight or until. the stopmechanisni is voluntarily released from its hold ing position.

Another object is to prevent the operation of the car starting mechanism in case the door on any one of the floors leading to the elevator shaft should be open.

A further object is to provide means controlled by the primary startingvalve for looking all of the doors in theirclosed positions, except that corresponding to the floor with which the car may be registered.

A still further object is to provide means controlled by the car for automatically releasing the door-locking means when the car is registered with the corresponding floor.

Other objects and uses will be brought out in the following description.

In the drawings- Figure 1 is an elevation, partly diagrammatic, of an .hydraulic lift or elevator system including the controlling mechanism forming the subject-matter of my present in- Specification f Letters Patent.

Patented June 24, 1919.

vention, the car and piston being shown by dotted lines, while the several floors are indicated in section. 1

Figs. 2 and 3 are enlarged slde and front Fig. 5 isan inner face view of the upper set of motor-controlling valves shownmn Fig. 1, together with the means for operat ing said valves from one of the floors inde pendently of the controlling means within the car. i

Figs. 6 and 7 are detail sectional views takemrcspectively, on lines 66and 7+7,

Fig. 8 is an elevation, partlyin section, of

the automatic car-stopping device for stops,

ping and holding thecar at anypredetermined floor, a portion of the car being shown in elevation with a locking bolt thereon.

. Figs. 9, 10, 11 and 12 are detail sectional views, taken respectively, 1 on lines 9 9,

10 -10, 11 11 and 1212, Fig. 8, except, that the dial andjindex fingerfor indicating in Figs. 9 and 11, is omitted.

Fig. 13 is av face view of the dial and index finger shown in Figs. 9 and 11.

Fig. 14 is a horizontal sectional view through a portion of the locking device shown 1 in Fig. 8, and adjacent portion of i the car upon which it is mounted. p

In order that my invention may be clearly understood, 1 have shown a portion of an hydraulic lift or elevator comprising a cylinder' -A having vertically movable piston a-carrying at its upper end a car a"--, which, together with the piston a, are shown by dotted lines in Fig. 1, as movable in an opening or well through any one or more of thefloors -bof a building. lhe cylinder A is connectedin the usual manner by a pipe 0; to a main conthe floor atwhich the car is stopped, shown trolling valve 1 having an inlet pipe wardly extending toothed rack 6 meshlng W1th a pinion, not show-n,-on a rotary shaft 8 which is journaled in-the upper end of the main valve case and is provided with an external drum 9 and a sprocket wheel 8, either of which may be employed in a manner hereinafter described for operating the, main valve.

An endless cable 10- is extended vertically through the elevator shaft and has its lower portion wound with one or more turns around thedrum and its upper portion supported by suitable sheaves 1l, preferably; at the top of the elevator shaft so that the opposite-sides .will be disposed in substantially parallel. vertical lines.

The main controlling valve ispreferably operated through, the medium of an auxiliary hydraulic controller forming the subject matter of my Patent No. 1,206,763, previously; referred to, and consisting, in this instance, of a reversing water motor 12 having its rotor connected through the medium of a gear train; 19 and clutch 20-- to a sprocket Wheel 23 which in turn is connected by a link belt -22 to the sprocket wheel -8 so thatwhen the sections of the clutch are engaged, the main valve will be raised'or lowered according to the direction of movement of therotary ele ment of the motor.

The. fluid for operating the motor is supplied through apipe. 24l leading, in this instance, from-the inlet pipe 2 of the main valve 1 through a normally open primary valve.25,itoa valve case 26, the valve chambers of: the case -26? being connected byseparate branch pipes 27 to the motor 12+ at opposite sides of the axis ofthe 'I'Ol'JOI"2fOI operating said rotor in in one direction or the other. according to the position of the valves 28- in the case 26-.

Connected ,in each'of the branch pipes 27 is a normally closed motor-controlling valve ,29 and a piston motor or hydraulic jack -30, each jack being connected in its branch z-27 between the corresponding valve 29 and motor .12 for controlling; the operation. of the clutch I 20,; and thereby, controllingthe transmission, of-m0ti0n from-the motor to the main Valve in. a manner, hereinafter described. .1

The pistons of the hydraulic jacks 30. are normally positioned to close communication between their respective valves .-29- and motor, but when either of the valves -29 is opened the motive fluid is admitted to thecorresponding jack, thereby operating itspiston to open communication between said; :valve and the motor for operating the rotor in one direction.

The means .fortransmitting motion from the hydraulic jacks 30 to the clutch 20 consists, in this instance, of a lever 51 pivoted to the motor case and resting upon the outer end of the piston rod of one of the jacks and provided with a pivoted link 52 which rests in a similar manner upon the upper end'of the piston rod of the other jack, as shown more clearly in Fig. 2, the lever 51 being connected by a retracting spring -61 to a stationary support, as 60, for yieldingly holdingthe pistons of the hydraulic jacks 30 in their normal positions.

The lever -51 is connected by a link 53 to a centrally pivoted lever 54- which in turn is connected by a link 55- to one end of a superposed centrally pivoted lever 56 having its opposite end connected by a link 57 to a clutch-operating lever 58.

This clutch is normally released to break the driving connection between the motor and main valve, but it is now evident that when either of the motor-controlling valves -29 is opened, while the primary valve 25 and secondary valves 28- are in their normal open positions, the motive fluid will be admitted to the corresponding jack -3,0-, thereby elevating its piston to first throw the clutch 20 into operative position and then to open communication with the corresponding side of the motor for driving the rotor to open the main valve and thereby establish communication between the cylinder A and either the inlet -2- or relief port 3 according to the direction in Which-it is desired to move the elevator Suitable means. is provided for operating the valves.29 from within the car, said means consisting, in this instance, of a cable 31 supported near the top of the elevator shaft by sheaves 32 and having a portion thereof extending into the car and suitably, connected to a hand-operated controller 33, the opposite sides of the cable being extended downwardly around suitable idlers 34; on the movable members 35 of an equalizer and attached to the under side of the car while the members -35 are connected by cords 36 to the stems of the valves 29, so that when the controller -33 is moved from its normal position in one direction, it will open one of the valves 29, and when moved in the opposite direction will open the other valve 29, the opening of either valve causing the operation of the motor and main valve actuated thereby for moving the car as may be desired according to the direction of movement of the controller 33-.

Automatic stop mechanism for motor and main oaloe.

Suitable means is provided for limiting the movement of the main valve andmotor when once set 111 motion by the opening of extreme position,

nee'avse either of the valves -29--, and for this purpose the stems of the secondary valves -28- i are extendedthrough opposite ends of the valve case 26- and 'pivotally connected to suitable levers -73- which are flexibly connected at one end to stationary portions of the valve case -26 by links -74c, while their opposite ends are pivotally connected to opposite ends of a vertically movable rod 71- having adjustable shoulders or collars i'2- thereon for receiving between them a forked arm on the upper end of the stem --6 of the main valve -1- so that as the main valve is shifted in either direction to cause the operation ofthe car, it will cause a corresponding movement of the rod -7 1- in the same direction to close the valve 28 of the branch -27-- corresponding to the previously opened valve -29--. thereby cutting off the supply of the.

motive fluid to the motor to stop further rotation of the same, and also causing the stoppage of the further movement of the main valve while the latter is still opento permit the elevator to continue its movement.

The car may be stopped at any desired destination by simply reversing the controlin the car to its other by which operation the previously opened valve --.29: will be closed and its companion valve opened, thereby causing a reverse operation of the motor and consequent restoration of the main valve to its closed position, and at the same time restoring the valves -28 to their normal positions, at which time the car will be stopped and the operator will then instantly return the controlling member --33- to its neutral position for closing the valve --29- last opened, thus stopping the motor.

I have thus far briefly described the auxling member -3$ iliary hydraulic means for operating the main controlling valve as used in connection with the controller within the car in order that the remaining features of myinvention used inconnection therewith may be more clearly understood.

Externally controlled startiotg and stopping dem'ce.

Suitable external means is provided whereby either of the valves -29- maybe opened from any one of the several floors of the building independently of the controller -38 within the car for causing the operation of said car through the medium of the motor and main valve, and forythis purpose the valve rods -37- are extended vertically through or adjacent to the elevator shaft at theseveral floors or stories with adjustable shoulders or collars -40- which are held in their adjusted positions-by set screws and are adapted to be t engaged by separate operating mechanisms,

one at each floor for raising or opening the valves 29- one at a time from their normal closed positions.

Each of these valve-operating mechanisms preferably comprises a horizontal rock shaft -41- suitably mounted in or upon the link 4l3- engaging the under side of the corresponding shoulder l0- of one of the valve rods 37-, wh le the other crank arm is connected by a hnk l4t to one end of a centrally pivoted lever -fl5von a station ary portion 4-8 of the frame of the elevator shaft, the opposite end of said leverbeing provided with a forked link -l6- engaging the under side of the shoulder 40 on the other valve rod --37-,

These rock shafts L1- preferably 02(- tend to the exterior of the elevator shaft at the several floors or stories of the building within easy reaching distance of the operator and are provided on their outer ends with suitable operating levers -l7- by which they may be rotated in reverse directions from a normal 13081131011, or such position as a will allow the valves "29 to close by the weight of their respective rods vs-37, the connections between each rock shaft and the valve rods being such that when the hand lever -l7- is rocked in one directlon it will open one of the valves without disturbing the other valve, and when rocked in the opposite direction will open the other valve without disturbing the first named valve with the result that the opened valve will cause the operation of the motor to shift the main valve from its neutral position, and thereby allow the motive fluid to operate the car in the desired direction.

It is now clear that the effect of opening and closing either of the valves -29-- by the external controller is substantially the same as that described for the in ternal controller -33, in that its movement in one direction causes the car to ascend and in the reverse direction to descend and that when it is desired to stop the car at a predetermined destination or floor, it is simply necessary to reverse the operation of the lever from one extreme position to the other, and then to return it to neutral or normal position when the ear comes to a stop in the manner previously explalned.

Emtemal floor-selecting and car-stoppin demlce.

Suitable means is provided whereby the operator at any one of the several floorsmay cause thecar to automatically stop at the same or any other predetermined floor and to remain in registration with such floor 11nl 'of the keepers screws to the rock shaft -101- atopposite ends of the'keeper 107 with suflicient clearance to allow the keeper to move a limited distancealong and upon said shaft and guide rod.

The guide rods 109and their supportingbrackets 109 constitute means for carrying the keepers rotarily about the axis of the rock shaft -10I and also for lockwith and permit their vertical movement thereon, the several keepers being disposed in different vertical planes about the axis of the rock shaft, and, therefore, at-an angle to each other, and bein preferably arranged spirally from one on to the other of the series so that by rocking the shaft they-may be successively brought into the for automatic interlocking engagement with a locking bo1t 113 on the car a-, as shown more clearly in Fig. -8.

Each keeper is provided with apertured sidewisealong the stud '116"to d 'said'lockingbolt from the keeper, but it is to same plane arms 1l0 in spaced relation one above the other for receiving the adjacent side of the cable 10 a series of stops for each keeper, each stop or abutment being located between the arms -110- with its ends adjacent thereto so that the slightest vertical movement 'of the keeper in either direction will produce a corresponding movementof the cable and the mam-controlling valve 1' operated thereby for restoring the car which in case such 'car should 'shift by settling or otherwise out of registration with the floor at which it may have been stopped.

The-outer'ed'ge of each keeper is convexed' or beveled fromits ends toward the center where'it is provided with'a central recess l1t for receiving the adjacent end of the locking bo1t3l13 on the car when adjusted into the path of movement'of said to which aretightly secured or abutments ll2, one

may be interlocked with one bolt, so thatwhen the main valve 1 is opened to cause theoperation of the car in either direction, the slde of the cable -10 carrying the stops 112' will be correspondingly shifted in a direction opposite to'thatof the movement of the car, and it, follows that 'if any one of the therefore,

- against the nearest -.s1-1iiicliently stiff to cause 113- to carry "car reaches that particular automatically stopped by the engagement of "keepers is adjusted'rotarily into the path of movement of the locking bolt l13- on said "car;-' said bolt'will autoumtically ride inclined face of the 'keeperumtil' it registers with the recess 114 into which it would be forced by aspring -1l3', thereby locking the keeper to'thecar and causing it, together with the adjacent side of the cable 1()-,to move therewith until the main valve is restored to its closed position for stopping the car at 'thepredetermined floor at which '13] 1e corresponding keeper is set.

"In "order to prevent any possibility of overstraining'or breaking the locking bolt or keeper with which it may be interlocked, "the boltis mounted upon a stationary stud or bolt -116 onthe car between two co- 'axial members -117 and 118, one of which, as the member 118-, consists of a rubber cushion or equlvalent yielding device,

I "while theother is'provided with a V-shaped ing the keepers to said shaft to rotate therecanrgro'ove '-1l9 receivinga V-shaped projection *120 on the adjacent side of thelocking' bolt113-, sothat if the-locking bolt is overstraincd it will sin'i fly'turu upon the stud 'l16-,thereby causing the "engaging 'cam'facesto force the locking bolt isengagc be understood that the cushion'-118 is *the' locking bolt the keeper with the car when -interlocked therewith under ordinary conditions- "Separate devices are provided at each floor for rocking 'the upright shaft -101- ;to'-brin'gany one of the keepers 107- into the path" ofmovement of the locking bolt -"-*1l3- on'tl1e"c'ar,'-each of said devices comprising a horizontal rock shaft -l0 having one end journaled in a yoke on the rock shaft 101- and provided with a pinion 103 meshing with a gear -104.- on said rock shaft, and its opposite-endyextended-to the exterior of'the elevator shaft within the corridor'or hall -avl1ere it is provided with a l1a11d-lever'106 within easy reaching distance of the operator.

This lever is preferably madein the form of a pointer and is movable around a dial 122 bearing the numbers of the several turning the pointer'to any one of the numbers, the rock shaft will be correspondingly turned' to bring the keeper at the floor corresponding to the number with-which the pointeris registeredon the 'dial intothe path of movement-of the'locking belt "113 on the car so that when the 'fioor, it will be the locking bolt -1l8' in "the recess 1 14 'in the'manner previously described.

'The'openings in the arms 1l0- of the keeper through which the cable -1() ex tends are preferably elongated circumferentially and concentric with the axis of the shaft l01- so as to enablethat side of the cable toiremain in a substantially straight:

line as the keepers are shifted rotarily.

Door and car loo/c anclrelcase.

shaft is open and forpreventing the open 111g of any one of the doors except the one w corresponding to the floor with which the car is registered, under which conditions such door will be automatically released from its locked position.

For this purpose, the stem, as-77-,of

the primary controlling valve Q5-- is extended vertically through the several floors in proximity to the doors, as 76-, leading to the elevator shaft, and serves, by its own weight, to normally hold said valve open, the stem -77 being provided at intervals with adjustable stops -80-, one for each door, held in their adjusted positions by set screws -.-81and normally resting upon the upper faces of the short arms of a series of door-operated levers 78--, as shown more clearly in Fig. 15. a

These levers are pivoted at 79- to the frame of the elevator shaft just above their respective doors -76- and are provided with inclined cam portions --83- at one side of theirpivots opposite that engaged by the shoulders --80- on the valve stem -7 7- said cams being inclined upwardly and extended in the direction of movement of the door.

The door is provided with an upwardly extending arm or bracket -86 carryinga roller -84- which rides upon the upper edge of the lever 78-- and is adapted to engage the incline or cam --83 as the door is opened for operating the lever to raise and thereby close the valve 25, the free end of the lever being guided in a slotted member 82-, thereby cutting off the supply of motive fluid to the auxiliary control- 10]" and preventing the operation of the car until the door is closed', which is effected automatically by means of a cord -91- passing oyer a sheave 9Q on the frame of the well and having one end connected to the door and its other end provided with a weight -90-; a a

Any suitable means may be providedfor locking each door in its closed position, said means consisting, in this instance, of a latch lever -S7- centrally pivoted at --94: to a plate -89-- on the frame of the elevator the door and its other end. engagedwith a roller bearing -95- which is engaged by a U-shaped operating member -88-+ jour naled upon ithe plate 89-+ and provided with curved cam faces-88 for releasing the catch 87- from itslocking position as said memberis rocked in either direction from its normal position.

This rocking member .-88- is provided witha radially pro ect ng arm carrying a roller 99 normally disposed in the path of movement of a cam member 100-- on the adjacent side ofthe car -a"-.-, said cam member .100 and roller 99- being so relativelyvarranged that the car moving in either direction will automatically operate the tripping mem.ber -88 to releasethe catch -87+from its lockingposition only when the floor of the car is registered with a floor of the building, the cam being yieldingly held in its normal position by springs -97-- to allowthe catch ---87-- to engage its keeper p i When the elevator doors are closed, their corresponding rollers .8A- are in close proximity to. the low point of the cams -83- of thelever -178., thus permitting the primary valve Q5- to normally remain open, which in turn allows the passage of the motive fluid to the motor when either of the valves -27- is opened for operating the main valve 1-eto allow the operation ofthe car in the manner previously. de-

scribed. a a

jOn the other hand, if any one of the doors is wholly or partially open, the long arm of the lever 78- will be depressed by the movement of the roller -8i upon the cam -83., thus causing the shorter arm of the lever to closethe valve +25 and cut off the supply of motive fluid to the motorto prevent any possibility of its operation, orthe operation of the car by either i the internal controller "33- or the external controller -4r-'Z--. while any one of the doors remains open.

On the other hand, when doors are all locked and the car is set in motion in either direction, it willcause the release of the door locking catches successively as itpasses through the several floors but only at the time when the car-floor is registered with the several floors of thebuilding, so that ifthe car is stopped at any particular floor, the adjacent catch will be held in [its released position by the engagement of the camlock +100 with the roller -99? on the lever -98, it being understood that as soon asfthe car passes any particular floor in its movement, the catch will be instantly land automatically,returned to. its normal giholding position.

well, said latch having one end engaged t In order that anoperatoron particnlar with a keeper. -93- -on the upper end of fisoor may start the elevator and cause it to automatically stop at the same or any other floor, it issimply necessary to set the lever -l06-' into registration with the number on the dial -122-, corresponding to the V floor at which the car is to be stopped. by

which operation the keeper'107 will be moved into the path of movement of the locking bolt -113 on the ear, whereupon the same operator may turn the hand-lever 4'Z*from its normal-position to open the proper valve ,29 which will cause the operation'of the motor and the consequent movement of the car until the locking bolt -113+ on the car interlocks in the registering keeper 107 at the floor where the car is to be stopped.

This interlocking movement of the locking boltwith the keeper causes the movement of the cable l0 to restore the main valve to its elosedposition in the manner previously described, thereby stopping the car at the predetermined floor where it will remain as long as the locking belt 113 and -keeper 107+ are'interlocked.

Y Incase the ear' should tend to settle sufliciently to bringits floor out of registration" with they floor of the building at which it was stopped, it would carry the keeper '1O7 and adjacent side of the cable 10-', thereby" again opening the main valve and causing the car to ascend until restored into registration with the floor.

What I claim is:

l, Controlling mechanism for elevators comprising, in combination, a. main valve, a. water -.motor. for operating said, valve. a

supplemental valve normally cutting off the,

waterisupply to the motor, means operable from different landings for adjusting the supplemental valve to permit the flow of waterto,saidfmotor, and means actuated by I themain valve for cuttlng off the water sup;

ply to the supplemental valve when the main valve is opened, the first named means being self-restoring and acting to restore the sup.- plemental valve to its normal position when thewater supply is cut ofi' therefrom by the.

second named means. 7 v

2. Controlling mechanisn'i for elevators comprising,

respondingiside of the motor, and means actuated 'by the valve when opened by the motor for cutting oil the water supplytorsaid supplemental valves,. said self re- G opies of this patent may be obtained for five cents each, by addressing the incombination, a main valve, a I reversing water meter.. for operating said self. restoring, means operable at will storing means acting to restore the adjusted valve to its normal position When the water supply is cut off thereto.

3. Controlling mechanism for elevators comprising, in combination, a main valve, :1. water motor for operating said valve, asupplemental valve normally cutting off the water supply to the motor, and means operable from difierent landings for adjusting the supplemental valve to permit the flow of water to said motor, said means including a rod of sufficient weight to restore the supplemental valve to its normal position when the water supply thereto is cut off.

.4. Controlling mechanism for elevators comprising, in combination, a main valve, a rotary reversing water meter for operating said valve, supplemental valves for controlling the water supply to opposite sides of the motor and normally cutting off said supply, means operable at will in reverse directions from one of the landings for adjusting either of the supplemental valves independently of the other to permit the flow'of water to the corresponding side of the motor, said means being self-restoring and acting to restore the adjusted valves to their normal positions when the water supply thereto is cut oii.

5. Controlling mechanism for elevators comprising, in combination, a main valve, a rotary reversing-water motor for operating said valve, supplemental valves for controlling the water supply to opposite sides of the motor, and normally cutting of? said supply, means operable at will in reverse directions from, one of the landings for adjusting either of the supplemental valves independently of the other to permit the flow of Water to the corresponding side of the motor, said means being self-restoring and acting to restore the adj usted valves to their normal positions when the water supply thereto is cut ofl, and means actuated by the main valve when, opened for cutting oil the water supply to the previously adjusted supplemental valve.

6. Controlling, mechanism for elevators comprising, in combination, a main valve, a water .motor for operating said valve, a supplemental valvenormally cuttingofl the water supply to v the motor, means operable from. different landings for adjusting the supplemental valve to permit the flow oi \vater to said motor, and car-operated means for restoring the main. valve to its neutral position after the restoration of the first named means.

1 In witness whereof I have hereunto set my hand this 30th day of October, 1916.

ADOLPH B. ROVER.

Commissioner of Patents,

Washington, D. 0. 

